BIND problem

I have registered my domain, lets say abc.nl, with a registrar. I changed the primairy DNS Server, through their control panel, to ns1.abc.nl. On ns1.abc.nl I run ISPConfig, so ns1.abc.nl is also my web and mail server. I've set the DNS settings to ns1.abc.nl so every domain, including abc.nl, that I created in ISPConfig has as primairy dns: ns1.abc.nl. As secondairy I can use the dns server of the registrar.
I have created my abc.nl domain and added the A record ns1 with IP 81.171.x.x.
I changed the TTL to 900, so I can make quick changes when I want.

When I do a DNS check I get this error for domain abc.nl
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FAIL No NS A records at nameservers WARNING: Your nameservers do not
include any corresponding A records when asked for your NS records.
They probably are not returning the A records when asked, which can
prevent some other DNS servers from contacting your DNS servers. They
should do this if they are authoritative for those A records (in BIND,
you should not use 'minimal-responses yes;'). The problem record(s) are:

Nameserver 80.69.67.67 did not provide IPs for all NS records.
Nameserver 80.69.69.69 did not provide IPs for all NS records.
Nameserver 84.246.22.10 did not provide IPs for all NS records.
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Above IP Addresses are the addresses of the registrars DNS servers. My ns1.abc.nl has the ip 81.171.x.x
What could be the problem?
When I dig abc.nl I get
;; AUTHORITY SECTION:
abc.nl. 900 IN NS ns1.registrar.net.
abc.nl. 900 IN NS ns1.abc.nl.